When the Senate of 1789 convened in New York City, members chose as their first chaplain the Episcopal bishop of New York. When the body moved to Philadelphia in 1790, it awarded spiritual duties to the Episcopal bishop of Pennsylvania. And when it reached Washington in 1800, divine guidance was entrusted to the Episcopal bishop of Maryland.

During its first 20 years, the Senate demonstrated a decided preference for Episcopalians. Among the initial 12 chaplains were one Presbyterian, one Baptist, and 10 Episcopalians.

Through the nineteenth century, Senate chaplains rarely held office for more than several years, as prominent clergymen actively contended for even a brief appointment to this prestigious office. With the twentieth century, however, came year-round sessions and the need for greater continuity. The office became less vulnerable to changes in party control. Appointed by a Republican Senate in 1927, Reverend Z. T. Phillips—the Senate's 19th Episcopalian—continued after Democrat's gained control in1933, serving a record 14 years until his death in May 1942.

On October 10, 1942, the Senate elected its 56th chaplain, the Reverend Frederick Brown Harris. The highly regarded pastor of Washington's Foundry Methodist Church, Harris failed to survive the 1947 change in party control that led to the election of the Reverend Peter Marshall. When Marshall died two years later, the Senate invited Reverend Harris to resume his Senate ministry. With his retirement in 1969, Harris set the as-yet-unchallenged service record of 24 years.

More than any of his predecessors, Harris shaped the modern Senate chaplaincy. Members appreciated the poetic quality of his prayers. On learning of President John F. Kennedy's assassination, Harris went immediately to the Senate Chamber. He later recalled, "The place was in an uproar. Senate leaders Mike Mansfield and Everett Dirksen asked me to offer a prayer. I called upon the senators to rise for a minute of silence, partly because of the gravity of the tragedy, but partly to give me a minute more time to think of something to say."

Borrowing from the poet Edwin Markham, he said, "This sudden, almost unbelievable, news has stunned our minds and hearts as we gaze at a vacant place against the sky, as the President of the Republic, like a giant cedar green with boughs, goes down with a great shout upon the hills, and leaves a lonesome place against the sky."